1. Field of the Invention
The present invention relates to a method for searching a signal source, and more particularly, to a method for searching an input signal in signal terminals.
2. Description of the Related Art
The progress of multimedia apparatuses (for example, a digital television, a projection system and a TV tuner) and the demand on the high image quality thereof make a multimedia apparatus need to equip with diverse signal terminals so as to be capable of inputting audio and video signals (AV signals) in a variety of formats.
As a multimedia apparatus is turned on, it usually needs some time to search and determine which signal terminal gets an input signal and what signal format the available input signal belongs to. Referring to FIG. 1, to do the job, a fixed search sequence is used in the prior art, for example, beginning with a digital visual interface (DVI) connector, then, an RCA connector, a Composite connector and ending at a Scart connector. When a user starts up a multimedia apparatus or presses down a search key, the multimedia apparatus follows the specified search sequence to sequentially search a signal source (step S110). Wherein, the DVI connector is detected at first to identify whether an input signal is available thereat (step S120). If input signal is found at the DVI connector, the input signal is analyzed and decoded (step S130) and the procedure to search a signal source is ended. If no input signal is found at the DVI connector, the search continues to the RCA connector to decide whether an input signal is available thereat (step S140). According to the search pattern, it continues to the following the steps S150-S195 to search the signal source input to the multimedia apparatus.
If the terminal often used by a user is the one taking the last sequence position in the search sequence (for example, the Scart connector), or the user needs to switch two or more than two terminals for using the multimedia apparatus, the search procedure must begin with the DVI connector, followed by sequentially detecting all the successive terminals to locate the terminal with an input signal, which incur lengthy search time to complete the job. In addition, while the multimedia apparatus is receiving a signal and displaying an image through the RCA connector, if the format of the input signal at the RCA connector is suddenly changed, for example, from 480i signal format to 1080i signal format (it often happens, for example, switching the TV channels), the search procedure runs again for detecting all the terminals to retrieve the signal in 1080i format at the RCA connector, because there is no signal at all at the RCA connector at that point the signal format gets switched. Therefore, such a situation briefly interrupts the viewing image when the user is using the multimedia apparatus.